Wiring new layout for DCS

I'd suggest installing a multi-port terminal block such as the one pictured below and run your TIU output wires to the red and black posts at the bottom. You can then run your track power feeds from the ports on the terminal block to how ever many connections to the track are necessary or desired.

The terminal block should be mounted so that it's centrally located in your layout so that the power wires to the track spread out in a "star" like pattern, but it is not mandatory that all wires be of equal length.

It is ok to run both loops on one channel as long as you run enough power feeds, but it may be advantageous to split the loops between two TIU channels depending on what engines you are planning on running  and whether you want to keep the loops electrically separated, again depending on what your ultimate goal is.

If you decide to run the loops on separate TIU channels, just get another terminal block and run the second channel to that block and then power wires out to the other loop.

Richie

Sounds good.  As far as DCS goes. Since the digital signals travel on the feeder wires. Would shielded feeder wire be better ?

Barry's recommendation was twisted pair.

Is the twisted pair information in his book ?

The book says good quality stranded pair; 16awg for up to 50', 14awg for longer. Worked for me on a 20' x 16' with 22 blocks, 10 on fixed one and 12 on fixed 2.

Thanks John,

I’ve been looking thru Barry’s book and I don’t see twisted pair mentioned. However I would imagine twisted pair would be advantageous because of the communication signals.

........John (also in wny)

The DCS signal is centered around a 3.27mhz signal, so an RF transmission line is ideal to minimize external signal corruption.  The twisted pair works well, obviously it's hard to twist the tracks to continue that beneficial transmission line effect!

I'm running all my power districts (blocks) to one large set of terminals, that way I can mix and match to obtain optimum results if I have any signal issues.

Could someone comment on the use of shielded cable?  Would it be a benefit?

I would think twisted pair shielded cable might be a easier (and may even be cheaper) to obtain.  Shielded twisted pair speaker wire comes to mind.

In the process control world, we would use shield twisted pair for both mAmp and digital signals. In those cases, we were sometimes running hundreds of cables near or next to each other.

I think shielding may not be such a hot idea.  If you start capacitively coupling the signal to a ground shield, you may well attenuate the signal, the very opposite effect you're trying to achieve.  The twisted pair really simply minimizes the introduction of external EMI to the signal since any magnetic field cuts both conductors and is cancelled out, the whole purpose of twisted pair.

I think process control with all the EMI in that environment simply adjusts the drive of the signals to compensate for any losses from the shielding.  Also, the frequencies involved in the control signals may not be as sensitive to coupling to ground, lower frequencies will have less attenuation for a given capacitance to ground.

Thanks John.

I know if we did not use shielded twisted pair in the process world, that particular loop could be "influenced" by surrounding circuits.  Giving you false data.

I suspect some of those shielded cables for your process control is to keep the EMI from escaping from the cable, rather than protect that "signal" from EMI.

I was thinking of using this as a terminal block.  Instead of making one or using the MTH block

I like it, fuses and everything.

Where did you get that, and what did it cost?

Amazon has it for $28

Screw Mount 10 Position Power Distribution Fuse Module Board, for 5 to 32V
by Xiken
Learn more: https://www.amazon.com/dp/B08L...oding=UTF8&psc=1

I did see it someplace else for about $5 less but long lead time

I use the MTH terminal block. It is designed for simple installation, as the hot and ground connections from the TIU are already separated and connected to the terminal block, so that one side of the output connections is hot, and the other side is ground. With a normal terminal block, you need to add jumper wires between the output connectors.

I also found I had significant signal strength issues if I used more than 9 track drops (connections to the track) from one terminal block. Each terminal block is connected to a separate TIU channel, so with 4 channels, I have about 36 track connections around my layout, which is 11x22 ft, twice around the room main line with two 8 ft long yards off the main line.

@yardtrain posted:

layout will not be broken up into blocks.

The DCS star wiring system calls for each track feed being isolated from the others. You do this by cutting the rail that is connected to the red terminal of the TIU or using insulated rail joiners.

@yardtrain posted:

Amazon has it for $28

Screw Mount 10 Position Power Distribution Fuse Module Board, for 5 to 32V
by Xiken
Learn more: https://www.amazon.com/dp/B08L...oding=UTF8&psc=1

I did see it someplace else for about $5 less but long lead time

One problem I see.  Those bozos used straight slot screws, I'm sticking to Phillips screws from now on, much easier to deal with, especially if you're in an awkward position already working on them.

I am SLOWLY wiring my 16x17 layout (3-rail running DCS and TMCC thru 3 TIUs in super mode with 12 isolated blocks--no Legacy or conventional). My power sources are all 180W Lionel bricks. They have circuit breakers. I think those would pop before the fuse blew. So for my layout, I don't see the point of fusing the terminal blocks. I am just using old barrier strips from my junk box. No problems found so far (knock on wood and all other applicable superstitions).

Don

as MTH is no more in a couple of months time and your layout is HO why not go with a DCC system NCE or Digitrax. the MTH locos will run on it just fine and that and it will allow you to run any of the HO manufacturers locos as well. signal problems are not a problem with DCC and there is so much more available for DCC.

Oman, let me understand you.....from the terminal block we would run many power feeds to the same loop or multiple loops of track.  You are saying it is required to separate each power feed from another even if they are just X number of feet or connections from the other one in the same loop, going back to the same terminal block?  I get the idea of the DCS signal wants to see the same distance from out and back so this forces the signal to go back the same power feed instead of leaking to the next?  Seems I have heard conflicting but appreciate the definitive answer

@Rick Rubino posted:

as MTH is no more in a couple of months time and your layout is HO why not go with a DCC system NCE or Digitrax. the MTH locos will run on it just fine and that and it will allow you to run any of the HO manufacturers locos as well. signal problems are not a problem with DCC and there is so much more available for DCC.

DCS is still being supported, they spun that off to a small group of employees, so DCS will go on, if someone wants to use it. Personally if I had HO I would go with DCC, not DCS, simply because it isn't tied to any one company, and if the source of my DCC system went away, have a lot of choices *shrug*

"DCS is still being supported, they spun that off to a small group of employees, so DCS will go on, if someone wants to use it. "

Maybe.

For HO, no doubt, it would be DCC I would strongly consider.  As far as I know, all MTH HO locos can function with DCC.  Not always perfectly, and all features, but DCC is guaranteed to be around 1, 2, 5 and probably 10-20 years from now.  Just worth considering.

Going DCC on a 3-rail layout with TMCC/Legacy in the mix as well is a BAD IDEA, at least IMO.  It might be useful to think about the actual environment being considered...

@Don Merz 070317 posted:

I am SLOWLY wiring my 16x17 layout(3-rail running DCS and TMCC thru 3 TIUs in super mode with 12 isolated blocks--no Legacy or conventional).

When wiring turnouts especially in a yard configuration. I solder wires to every isolated rail. They are for the most tied into the existing wiring. Often times creating multiples in the same block on the same terminal. I also use basically common ground wiring for the most part because that’s what was there before DCS arrived. The layout was blocked.  Every 3 ft. Sections of Gargraves has feeders. I wasn’t about to re wire a large layout. Tweak Yes. Re Wire No. A lot of what I did was just clean things up. 12 gauge buss with 14 gauge feeders. Stranded automotive wire.
My advice. What ever wiring method you choose. Is test as you go along. Every section you add re test everything, fix before moving on and by all means. Don’t overthink this.

@Oman posted:

The DCS star wiring system calls for each track feed being isolated from the others. You do this by cutting the rail that is connected to the red terminal of the TIU or using insulated rail joiners.

You can do either. Or just leave the center (RED WIRE RAIL) Pin out and make sure the rails are NOT touching each other.

@gunrunnerjohn posted:

Going DCC on a 3-rail layout with TMCC/Legacy in the mix as well is a BAD IDEA, at least IMO.  It might be useful to think about the actual environment being considered...

John.  my advice was based on his stating that he was in HO not 3 rail. and as far as employees taking over the electronic part of MTH I have my doubts. MTH was for sale for quite some time with no takers and have heard rumors from friends in the industry that things are not going well in that regards to employees taking over the DCS side.. JUST A RUMOR NOT A FACT. Rick

Rick, I see we have two conversations going here, so there's confusion enough to go around!   The OP did say HO, then Don jumped in talking about 3-rail O.  I agree with you on the HO, that's a no-brainer.

@SteveMa posted:

Oman, let me understand you.....from the terminal block we would run many power feeds to the same loop or multiple loops of track.  You are saying it is required to separate each power feed from another even if they are just X number of feet or connections from the other one in the same loop, going back to the same terminal block?  I get the idea of the DCS signal wants to see the same distance from out and back so this forces the signal to go back the same power feed instead of leaking to the next?  Seems I have heard conflicting but appreciate the definitive answer

Yes, so you do want power blocks, although you don't need to electrically switch them. Each block has it's own power feed. Some people have had success with buss wiring, but some have not. So, may as well do what's recommended.

Terminal board has arrived.